autocad 2nd sem

Machine tools

• Machine which performs the material removal operation with tools

LatheJob is rotatedAnd cutting tool is advanced

shaper

shaper

Tool Reciprocating on a flat surface

Planer

Planer

• Tool remains stationary and work piece reciprocates.

• Used for large jobs

Drilling Machine(Multipoint cutting tool)

Grinding machine

MillingRevolving cutter with many teeth (multi

point) having a cutting edge each

sawing

Machine tools• Lathe• Shapers• Planers• Drilling• Grinding• Milling• Sawing

We will discuss• Lathe• Shapers• Planers• Drilling• Grinding• Milling• Sawing

We will also discuss

• Mechanics of chip formation• Types of chips

• Cutting fluids

Lathe Operations• Centering• Facing• Plain turning• Step Turning• Taper Turning• Drilling• Reaming• Boring• Undercutting or grooving• Threading

Lathe Operations• Centering• Facing• Plain turning• Step Turning• Taper Turning• Drilling• Reaming• Boring• Undercutting or grooving• Threading• Knurling

Lathe O

perations• Centering• Facing• Plain turning• Step Turning• Taper Turning• Drilling• Reaming• Boring• Undercutting or grooving• Threading• Knurling

Lathe Operations• Centering• Facing• Plain turning• Step Turning• Taper Turning• Drilling• Reaming• Boring• Undercutting or grooving• Threading• Knurling

Lathe O

perations• Centering• Facing• Plain turning• Step Turning• Taper Turning• Drilling• Reaming• Boring• Undercutting or grooving• Threading• Knurling

Mechanism of Chip formation

Proc

ess

of C

hip

form

ation

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Continuous DiscontinuousProduced while machining brittle metalsHigh cutting speedLarge depth of cutLarge rake anglesLack of effective fluids will produceEase of handlingGood surface finishHeat Produced in the chip is carried awayTool life

Continuous DiscontinuousProduced while machining brittle metals

No Yes

High cutting speedLarge depth of cutLarge rake anglesLack of effective fluids will produceEase of handlingGood surface finishHeat Produced in the chip is carried awayTool life


No Yes

High cutting speed Yes NoLarge depth of cutLarge rake anglesLack of effective fluids will produceEase of handlingGood surface finishHeat Produced in the chip is carried awayTool life


No Yes

High cutting speed Yes NoLarge depth of cut No YesLarge rake anglesLack of effective fluids will produceEase of handlingGood surface finishHeat Produced in the chip is carried awayTool life


No Yes

High cutting speed Yes NoLarge depth of cut No YesLarge rake angles Yes NoLack of effective fluids will produceEase of handlingGood surface finishHeat Produced in the chip is carried awayTool life


No Yes

High cutting speed Yes NoLarge depth of cut No YesLarge rake angles Yes NoLack of effective fluids will produce

No Yes

Ease of handlingGood surface finishHeat Produced in the chip is carried awayTool life


No Yes


No Yes

Ease of handling Less MoreGood surface finishHeat Produced in the chip is carried awayTool life


No Yes


No Yes

Ease of handling Less MoreGood surface finish ? ?Heat Produced in the chip is carried awayTool life


No Yes


No Yes

Ease of handling Less MoreGood surface finish ? ?Heat Produced in the chip is carried away

No Yes

Tool life


No Yes


No Yes

Ease of handling Less MoreGood surface finish ? ?Heat Produced in the chip is carried away

No Yes

Tool life ? ?

Factors responsible for Built-up Edge

• Excessive Pressure at the cutting edge• Machining of ductile materials with high

friction• rake angle• cutting speed• depth of cut• Blunt tool• High friction at tool chip interface

Continuous Chips with Built-up Edge

• Excessive Pressure at the cutting edge• Machining of ductile materials with high

friction• Low rake angle• Low cutting speed• Large depth of cut• Blunt tool• High friction at tool chip interface

BUE can be desirable because ?

BUE can be desirable because ?

A thin and stable BUE protects tool surface and reduces wear

BUE can be undesirable because ?

BUE can be undesirable because ?

Inferior surface finish

Cutting fluids

Cutting fluid advantages

• Lubrication – reduces friction• Absorbs and carriages away the generated

heat.• Washes away chips and any dust during

process.• Carry away the BUE• Prevent corrosion of the machined surface,

tool and machine

Disadvantages

Disadvantages

It cost to have pumps, filters, coolant tank etc

Disadvantages

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Disadvantages

Toxic vapor

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Disadvantages

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Disadvantages

Unpleasant order

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Disadvantages

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Disadvantages

Skin allergy

Disadvantages

Disadvantages

Corrosion

Disadvantages

Disadvantages

Flammable and can cause fire hazards

Principal parts of lathe

• Bed• Headstock• Tailstock• Carriage• Feed Mechanisms

autocad 2nd sem

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Transcript of autocad 2nd sem